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Title: Deep ultraviolet distributed Bragg reflectors based on graded composition AlGaN alloys

Distributed Bragg reflectors (DBRs) with peak reflectivity at approximately 280 nm, based on compositionally graded Al{sub x}Ga{sub 1−x}N alloys, were grown on 6H-SiC substrates by plasma-assisted molecular beam epitaxy. DBRs with square, sinusoidal, triangular, and sawtooth composition profiles were designed with the transfer matrix method. The crystal structure of these DBRs was studied with high-resolution x-ray diffraction of the (1{sup ¯}015) reciprocal lattice point. The periodicity of the DBR profiles was confirmed with cross-sectional Z-contrast scanning transmission electron microscopy. The peak reflectance of these DBRs with 15.5 periods varies from 77% to 56% with corresponding full width at half maximum of 17–14 nm. Coupled mode analysis was used to explain the dependence of the reflectivity characteristics on the profile of the graded composition.
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [3] ;  [1] ;  [2] ;  [2]
  1. Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215 (United States)
  2. (United States)
  3. Photonics Center, Boston University, Boston, Massachusetts 02215 (United States)
Publication Date:
OSTI Identifier:
22415096
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 22; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM ALLOYS; BRAGG REFLECTION; CRYSTAL STRUCTURE; GALLIUM ALLOYS; MOLECULAR BEAM EPITAXY; NITROGEN ADDITIONS; REFLECTIVITY; SILICON CARBIDES; SUBSTRATES; TRANSFER MATRIX METHOD; ULTRAVIOLET SPECTRA; X-RAY DIFFRACTION